In Python, for loops are used to iterate over a sequence (such as a list, tuple, string, or range) or any iterable object. Here's how you can use for loops:
my_list = [1, 2, 3, 4, 5]
for item in my_list:
print(item)
This loop will iterate over each element in the list my_list and print it.
for i in range(5):
print(i)
This loop will print numbers from 0 to 4. range(5) generates numbers from 0 up to, but not including, 5.
my_string = "Hello"
for char in my_string:
print(char)
This loop will iterate over each character in the string my_string and print it.
You can use enumerate() to get both the index and the value of each item in a sequence.
my_list = ['a', 'b', 'c']
for index, value in enumerate(my_list):
print(f"Index: {index}, Value: {value}")
my_dict = {'a': 1, 'b': 2, 'c': 3}
for key, value in my_dict.items():
print(f"Key: {key}, Value: {value}")
This loop will iterate over each key-value pair in the dictionary my_dict and print them.
You can nest for loops within each other.
for i in range(3):
for j in range(3):
print(f"i: {i}, j: {j}")
break statement:
You can use the break statement to exit the loop prematurely.
for i in range(5):
print(i)
if i == 2:
break
The continue statement can be used to skip the rest of the code inside the loop for the current iteration and proceed to the next iteration.
for i in range(5):
if i == 2:
continue
print(i)
Similar to while loops, you can include an else block with a for loop. The else block executes when the loop completes normally (i.e., without encountering a break statement).
for i in range(5):
print(i)
else:
print("Loop completed normally")
These are some common patterns for using for loops in Python. They are useful for iterating over sequences or performing repetitive tasks.